Liquid storage



March 1970 c. v. DETTER I 3,501,917

LIQUID STORAGE Filed June 14. 1968 ORIGINAL GRADE LEVEL FIG.

O INVENTOR. c. v. DETTER (.0

BY 5 :5 q Q '52 m A T TORNEYS United States Patent 3,501,917 LIQUIDSTORAGE Clyde V. Detter, Bartlesville, 0kla., assignor to PhillipsPetroleum Company, a corporation of Delaware Filed June 14, 1968, Ser.No. 737,028 Int. 'Cl. B65g 5/00; E211? 17/16 US. Cl. 611 9 'ClaimsABSTRACT OF THE DISCLOSURE In many regions there is an acute need for anefficient, low cost reservoir for collecting and storing surface water.In view of the fact that the soil in many arid regions is porous,temperatures are normally high, and winds may be quite strong,conventional open pit storage is not satisfactory. Water is lost fromsuch pits at excessive rates due to seepage into the soil andevaporation. While these storage pits can be lined with an impermeablematerial to reduce seepage losses, evaporation still is a major problem.Although various types of covers have been proposed in the past, thesedevices are either quite expensive or are not effective to eliminateevaporation losses.

These problems are solved in accordance with the present invention bythe use of a cover which is made of a relatively thin, flexiblematerial. For example, polyethylene film of approximately 10 milthickness can be employed. While film of this type meets the requirementof low cost, there is a serious danger that the film will be destroyedby wind action. This problem is overcome in accordance with the presentinvention by controlling the pressure within the reservoir between thesurface of the water and the film. In one embodiment, the pressure inthis region is reduced so that atmospheric pressure retains the film incontact with the surface of the water, and thereby prevents the filmfrom being whipped in the Wind. In another embodiment, the interior ofthe reservoir is maintained at an elevated pressure so that the sheetbellows out. This also reduces the tendency of the film to be whipped inthe wind, The pressure control within the reservoir can conveniently beaccomplished by the use of suction or blowing devices which are actuatedby the wind.

Accordingly, it is an object of this invention to provide an improved,low cost system for storing surface water.

Another object is to provide an eflicient method of collecting andstoring surface water in windy, arid regions.

Other objects, advantages and features of the invention should becomeapparent from the following detailed description, taken in conjunctionwith the accompanying drawing in which:

FIGURE 1 is a view, shown partially in section, of a first embodiment ofthe storage system of this invention. FIGURE 2 illustrates a secondembodiment of the pressure maintenance feature of this invention.

Referring now to the drawing in detail and to FIGURE 1 in particular,there is shown a reservoir 10 formed in the surface of the earth. Such areservoir can be formed by the use of a bulldozer or other dredgingdevice, and is located in an area to collect water which flows along thesurface following a rain. Reservoir 10 is surrounded by a dike 11 whichdefines the outer contour of the reservoir.

One or more filling pipes 12 can extend through the dike to permit thereservoir to be filled from the watershed area. These pipes can beprovided with suitable inlet screens 13 to prevent debris from cloggingthe pipes.

The base of reservoir 10 is preferably lined with a water impermeablematerial 14 to prevent loss of water into the soil. Various materialscan be employed for this purpose. For example, roofing material or feltmats formed of synthetic or natural fibers impregnated with asphalt canbe used to advantage in many areas. Liner 14 can also be formed of aflexible synthetic material, such as rubber or plastic sheeting. If thereservoir is to be formed in soil which is relatively impermeable, thisliner is not needed. However, in most arid regions a liner is necessary.The liner can be anchored at its ends to dike 11 by any suitable means.In order to prevent evaporation of water from reservoir 10, a cover 15is positioned across the top of the reservoir. This cover is made of arelatively thin flexible material, such as polyethylene film. The edgesof cover 15 are also anchored in dike 11 so as to cover the reservoircompletely. A delivery pipe 16 extends from reservoir 10 through dike 11to a stock tank 17 or other point of water usage. A valve 18 is providedin pipe 16 to control the withdrawal of water from reservoir 10.

As previously mentioned, it is desirable from an economic viewpoint touse a relatively thin, flexible material for cover 15. However, thisposes problems because the cover is likely to be damaged by wind. Inorder to avoid this problem, the pressure above the water in reservoir10 is adjusted to minimize movement of cover 15. As illustrated inFIGURE 1, a pipe 20 extends through dike 11 to a region above thesurface of the water in reservoir 10. The inner end of pipe 20 isprovided with guard rods 21 to keep cover 15 from closing the pipe. Theouter end of pipe 20 is provided with a rotary turbine ventilator 22 toincrease the draft provided by pipe 20. In this manner, wind blowingacross the top of the reservoir tends to evacuate the interior of thereservoir. The resulting pressure reduction forces cover 15 against thesurface of the water and thereby prevents the cover from whipping in thewind. An advantage of this system resides in the fact that any increasein wind velocity results in a corresponding decrease of pressure withinthe reservoir to hold cover 15 more tightly against the surface of theWater. While any means for evacuating the interior of the reservoir canbe employed, the ventilator is advantageous because it is inexpensive toconstruct and does not require any appreciable amount of maintenance.

A second embodiment of this invention is illustrated in FIGURE 2. Inthis embodiment, the pressure reducing means of FIGURE 1 is replaced byapparatus which increases the pressure within the reservoir. To thisend, a pipe 20' extends through dike 11 in substantially the same manneras does pipe 20 of FIGURE 1. However, the upper end of pipe 20' isprovided with a rotatable wind scoop 25 which faces into the windbecause of an attached weather vane 26. Air scoop 25 results in thepassage of air into the region 23 above the surface of the liquid sothat cover 15 bellows upwardly. In this manner, cover 15 tends to remainin a relatively stationary position so that wind damage is minimized. Inthis embodiment, pipe 20' is normally positioned within a region of dike11 upstream of the reservoir in the prevailing wind.

In view of the foregoing description, it can be seen that an efficient,economical reservoir is provided in accordance with this invention.While the invention has been described in conjunction with presentlypreferred embodiments, it should be evident that it is not limitedthereto.

What is claimed is:

1. A reservoir for liquids comprising:

means forming a chamber adapted to hold a liquid to be stored, saidchamber normally being open at the p;

a gas impermeable cover extending over said chamber and sealed to theedges thereof, said cover being formed of a flexible material; and

means communicating with the interior of said chamber to change thepressure inside said chamber above the liquid being stored, therebytending to displace said cover relative to the surface of liquid beingstored in said chamber, said means to change pressure comprising conduitmeans extending from the interior of said chamber above the surface ofliquid being stored to a region, exterior of said chamber, and

gas transfer means connected to said conduit means to pass gastherethrough to change the pressure above the surface of liquid in saidchamber.

2. The reservoir of claim 1 wherein said gas transfer means comprisesmeans to pass gas through said conduit means to said exterior region toreduce the pressure within said chamber above the surface of liquidbeing stored so that said cover tends to be forced downwardly intoengagement with the surface of the liquid.

3. The reservoir of claim 1 wherein said gas transfer means comprisesmeans to pass gas through said conduit means to the interior of saidchamber to increase the pressure within said chamber above the surfaceof the liquid being stored so that said cover tends to be forcedupwardly away from the surface of the liquid.

4. The reservoir of claim 1 wherein said chamber is formed in thesurface of the earth and further comprising:

second conduit means extending from the interior of said chamber to theexterior thereof at a region adjacent the surface of the earth tocollect surface water and pass same into said chamber; and

third conduit means extending from the interior of said chamber to theexterior to permit withdrawal of water from said chamber.

5. The reservoir of claim 4, further comprising a water impermeableliner covering the surface of the earth forming the bottom of saidchamber.

6. A reservoir for water comprising:

a chamber formed in the surface of the earth so as to be open at thetop;

a cover formed of flexible material extending over said chamber andsealed to the edges thereof;

first conduit means extending from the interior of said chamber to theexterior thereof at a region adjacent the surface of the earth tocollect surface Water and pass same into said chamber;

second conduit means extending from the interior of said chamber to theexterior to permit withdrawal of Water from said chamber; and

means to change the pressure inside said chamber above the surface ofwater being stored, comprising third conduit means extending from theinterior of said chamber above the surface of water being stored to aregion exterior of the chamber, and a ventilator secured to said thirdconduit means to Withdraw air from the interior of said chamber throughsaid third conduit means so as to reduce the pressure within saidchamber and thereby tend to force said cover downwardly into engagementwith the surface of the liquid.

7. The reservoir of claim 6, further comprising a water impermeableliner covering the surface of the earth forming the bottom of saidchamber.

8. A reservoir for water comprising:

a chamber formed in the surface of the earth so as to be open at thetop;

a cover formed of flexible material extending over said chamber andsealed to the edges thereof;

first conduit means extending from the interior of said chamber to theexterior thereof at a region adjacent the surface of the earth tocollect surface water and pass same into said chamber;

' second conduit means extending from the interior of said chamber tothe exterior to permit withdrawal of water from said chamber; and

means to change the pressure inside said chamber above the surface ofwater being stored, comprising third conduit means extending from theinterior of said chamber above the surface of water being stored to aregion exterior of the chamber, and an air scoop secured to said thirdconduit means to pass air into the interior of said chamber through saidthird conduit means so as to increase the pressure within said chamberand thereby tend to force said cover upwardly out of engagement with thesurface of the liquid.

9. The reservoir of claim 8, further comprising a water impermeableliner covering the surface of the earth forming the bottom of saidchamber.

References Cited UNITED STATES PATENTS 2,211,958 8/1940 Mahatfey 6l.5 X3,052,380 9/1962 Prins 6l.5 X 3,330,118 7/1967 Biais 6l.5 3,425,7912/1969 Koberg 6l.5 X

PETER M. CAUN, Primary Examiner

